Bristleworms: What to do?

Look closely at night, preferably with a flashlight, turning the beam on rocks and crevices. They are elusive, but I've seen mine several times. You can set a trap for them, although mine has never fallen for it. The traps are sold in some aquarium stores.

The damage to your stars sounds more like crabs than worms to me. I have a serpent star that lost all its legs to damage from hairy crabs. Miraculously enough, it has regenerated and survived for several years now. Anyway, you might keep an eye out for hairy crabs after lights out.

I have had bristleworms of various kinds and often large sizes for years, and have had little trouble with them. Large eunicids will take the occasional bite of a coral, and I have had a heck of a time with them eating my marine grasses. I have not lost a fish or other mobile animal to them, though. I won't swear that the worms aren't your problem, but I am dubious that they are the cause.

I would never put an arrow crab in a reef tank. It's a personal choice. To me, a reef should be diverse, and I don't like that arrow crabs eat fanworms, terebellids, and any other tasty little invert they can catch. The cure seems worse than the disease.

If I were to look for a culprit for the missing fish, I'd take a good look at the serpent star. Are you sure it's a serpent, and not a green brittle star? They are known fish eaters.

Sorry I can't be more helpful. The only useful thing I can suggest is to take ragc's advice and watch the tank after dark. It seems the best way of finding out who's causing the trouble.

The glass slivers could be from certain types of sponges, especially if it's always the same rock.

When viewing at night use red celaphane or red LED light to view the tank, the colour is not picked up by fishes eyes, so you can view them without them knowing you are watching them

CBS are good at hunting down bristle worms and will eat them, may be a wiser choice to get a coral banded shrimp instead of a arrow crab, arrow's become more aggresive and are not reef safe.

mogurnda said:

If I were to look for a culprit for the missing fish, I'd take a good look at the serpent star. Are you sure it's a serpent, and not a green brittle star? They are known fish eaters.

Click to expand...

An Arrow crab can eat smaller fish, or stated above.

If it is bristleworms...take a small water bottle...drill a hole through the cap and a similar hole through the bottom, a little larger than the diameter of the worms. Tie a string around it. Put a few small rocks or pebbles in the bottle to sink it and put several flakes or small pellets of food in there. Place one of the drilled openings in the tank near the crevice from which you have seen the worm/s come out of... and wait.

I've caught several this way.